Field of the Invention
The present invention relates to integrating virtual insertions into a video depicting an event, and more specifically to enhancing the integration of the virtual insertions by correcting for distortion caused by a lens of a camera capturing the event.
Related Art
An event, such as a sporting contest, a musical concert, a speech, a movie, a television sitcom, or a television reality show to provide some examples, may be captured by a broadcaster onto a video using one or more cameras. The video is subsequently broadcasted by the broadcaster to a remote viewer. The remote viewer observes the video near live as the event is happening in real-time, or after the event is complete, using a television platform, an internet platform, and/or a mobile platform to provide some examples.
Commonly, the broadcaster integrates virtual insertions, such as virtual graphics to provide an example, with the video using a virtual insertion and enhancement system to enhance observation of the event by the remote viewer. An example of such a virtual insertion and enhancement system is described in U.S. patent application Ser. No. 07/826,754, filed on Jan. 28, 1992, now U.S. Pat. No. 5,264,933, which is incorporated by reference in its entirety.
Performance of this virtual insertion and enhancements system can be limited by many factors. One such factor, commonly referred to as camera lens distortion, relates to unwanted distortion present in the video resulting from a lens of a camera capturing the event as it occurs. Conventional techniques to correct for the camera lens distortion may involve subsequent removal of the camera lens distortion from the video through a calibration process using calibration targets. This calibration process uses distortion curves having distortion constants as functions of zoom, focus, image distance, focal length, magnification, field of view, or other parameters to correct for the camera lens distortion in the video.
For many virtual insertion and enhancement applications, it may be necessary or desirable for these systems to operate with minimum setup time. A venue hosting the event may not provide support for the calibration process prior to the event. For example, the broadcaster may not be provided pre-event shots with the calibration targets. Additionally, the venue hosting the event may not provide enough time prior to the event to properly calibrate the camera lens or may allow enough time and resources for some aspects of the calibration but not others. Some events, like sporting contests to provide an example, may not have adequate event lighting necessary for calibration until close to a starting time of the event.
Thus, there is a need for an apparatus and/or a method to generate adequate lens distortion models or curves without time and resource consuming lens calibrations that overcomes the shortcomings described above. Further aspects and advantages of the present invention will become apparent from the detailed description that follows.
The present embodiments will now be described with reference to the accompanying drawings. In the drawings, like reference numbers may indicate identical or functionally similar elements.